I would suggest as an alternative to Zillow's zetimates is Rentometer: https://www.rentometer.com/I am not 100% sure on the accuracy of either but maybe trying multiple sources and comparing will give you a better idea of a more accurate range your property could fall in

Hey all, any thoughts on the importance to purchase small multifamily properties that do not have accurate property records listed with the county? For example, looking at a 4plex that is only showing 3 units on the c...

They should be able to review your analysis of a property and give constructive feedback on its accuracy.  

Anyone have experience with AirDNA and its accuracy, more specifically in Pittsburgh?

To get a better accuracy of what your actual numbers will look like, you can take into account vacancy rates in your market, are you doing a full rehab(electrical,plumbing, foundation,etc)?

Fannie Mae rules don't allow a tax return and a letter from my CPA stating the accuracy to be counted for rental income.

---------------------------------------------------------------------------------I question the accuracy  --and to a point, the relevancy-- of this statement.

You might want to hire a tax pro to review your prior years' taxes for accuracy and missed opportunities.As far as selling v. exchanging, I agree with your thinking: sometimes it's best to pay the tax when the tax hit is acceptable.

I want this to be completely transparent for accuracy.

My guess is that Tennessee (Pigeon Forge area) has WAY more data points, thus better accuracy.